Fuel supply systems

ABSTRACT

A petrol injection system for an internal combustion engine in which separate main injectors in main air inlet tubes feeding such port are supplemented by a constricted and possibly heated common air inlet tube having a further injector. The supplementary inlet tube is effective during idling and low power running and the main injectors and main air inlet tubes are used for higher powers, the supplementary inlet being phased out.

United States Patent Jackson [451 Aug. 22, 1972 FUEL SUPPLY SYSTEMS 3,444,848 5/1969 Lawrence ..123/122 [72] Inventor, Harold Ernest Jackson, plympmn 3,461,850 8/1969 Oblander ..123/122 St Mary England 1,894,510 1/1933 Ensign ..123/75 B Devon, England 2,793,633 5/1957 Heftler ..123/122 2,884,913 5/1959 Heintz ..123/32 STR [731 Asslgneei Petrol "1 m" lllmled, Plymouth 3,443,552 5/1969 Von Seggern ..123/75 B 22 Filed; 3 1970 3,444,848 5/1969 Lawrence ..123/122 3,456,634 7/1969 Nelson ..123/75 1 1 p N91 68,513 3,461,850 8/1969 Oblander ..123/122 3,543,736 12/1970 Suzuki ..123/122 Related US. Application Data Continuation of Ser. No. 756,849, Sept. 3, 1968, abandoned.

Foreign Application Priority Data Sept. 4, 1967 Great Britain ..40,383/67 US. Cl. ..123/127, 123/75 B, 123/119,

123/122 lnt. C1,...F02m 13/04, F02m 31/00, F02b 33/00 Field of Search ..123/75 B, 122, 127, 32.4

References Cited UNITED STATES PATENTS Primary Examiner-Laurence M. Goodridge Assistant Examiner-Ronald B. Cox Attorney-Holcombe, Wetherill & Brisebois 5 7 ABSTRACT A petrol injection system foran internal combustion 5 Clains, 4 Drawing Figures Patented Aug. 22, 1972 2 Sheets-Sheet 1 lbs RM H WcHw m MM 3 EM H BY Mm.

load operation of the engine the inlet gas velocity is low so that the air-fuel mixture is uneven, leading to uneconomical use of the fuel and undesirable constituents such. as carbon monoxide and unbumt hydrocarbons in the exhaust gas of the engine.

It is an object of the invention to reduce this difficul- According to the invention there is provided a fuel supply system for an internal combustion engine including a plurality of intake tubes connected to the inlet ports of the engine, a plurality of means for introducing fuel into the respective intake tubes separately and first meansfor regulating gas flow effective on the entry to the intake tubes, wherein there is provided a further tube of relatively small cross-see tional area, further means for regulating gas flow effective on the flow in the further tube and further means for introducing fuel into the further tube, said further tube also being connected to the inlet ports of the engine, said first and further regulating means being coupled so that when the engine is running at low power the entire gas flow takes place through the further tube and for higher powers the first regulating means allows the entry of gas into the intake tubes.

In order that the invention may be fully understood and readily carried into effect it will now be described with reference to the accompanying drawings, of which FIG. 1 is a cross-sectional diagram of one example of the fuel supply system according to the invention,

FIG. 2 is a perspective diagram showing the layer of components of the example of the invention shown in FIG. 1 applied to a four-cylinder engine,

FIG. 3 is a diagram of the fuel supply control for the system shown in FIGS. 1 and 2 and FIG. 4 shows a detail of the system shown in FIGS. 1, 2 and 3. g

In FIG. 1 reference 1 indicates an inlet port of an intemal combustion engine, the port being in the cylinder head of which part is indicated by reference 2. An intake tube 3 is provided aligned with the port 1 and joined thereto via a gasket 4 by, for example, bolts or studs which are not shown in the figure. The tube 3 is connected to a plenum chamber 5 which is common to a plurality of intake tubes. Although only one intake tube 3 is shown in FIG. 1 it will be appreciated that in general several intake tubes will be provided and there may possibly be one intake tube for each cylinder of the engine. The intake tube 3 is provided with an injection nozzle 6 coupled by means of the flexible pipe 7 to a fuel pump and regulating valve not shown in FIG. 1. It will be appreciated that each intake tube 3 will be provided with a separate injection nozzle 6 coupled to the fuel pump and regulating valve.

The plenum chamber 5 is provided with a main air entry tube 8, coupling to the atmosphere either directly or through suitable air cleaning means. The tube 8 includes first and second throttle valves 9. and which as shown are of theconventional butterfly type,- but they may be of any other suitable form. Between the throttle valves 9 and 10 there is a region 11 provided with a lateral hole 12 which is coupled by means of the tube 13 to a, gallery 14 whichfextends alongside'the plenum chamber 5. Constructed integrally with the gallery 14 is a manifold 15 which iscoupledby means of one or more apertures 16 to the gallery 14, and manifold 15 also has outlet-orifices l7 matching similar orifices 18 provided in'the side walls of the intake tubes 3. The gallery 14 is joined to exhaust pipe 19 so as to-be in good thermal contact therewith. Reference 20 in-' dicates twodotted concentric circles which represent a further injection nozzle provided for the injection of fuel into the air stream flowing along the tube 13 into the gallery 14.

The operation of the arrangement shown in FIG. 1

will be described starting with-the throttles 9 and 10 both closed. It' should be pointed out at this stage that initially only thethrottle 9 opensand after it is opened to a predetermined extent further opening of the throt onlyopen airflows into the region 11 and because the throttle 10 is closed it is directed along the tube .l3 into the gallery 14 which is heated by heat transfer from the exhaust pipe 19. At theend of the gallery 14 past which the air from the tube 13 flows into the gallery 14 fuel is injected by means of the injector 20 and this fuel in the heated atmosphere and on contact with the walls of the gallery 14 is vaporized and forms an air-fuel mixture of substantially uniform proportions. The air-fuel mixture passes through the hole 16 into the manifold 15 and from there through orifices 17. and 18 into the intake tube 3, from which it isfed into. the inlet port 1 of the engine. A similar air-fuel mixture is fed via the otherintake tubes into the other ports of the engine.

As the throttle 9 is opened more widely an increasing volume of air is fed along the tube 13 and so that the engine is able to develop more power .in the usual way. At a certain predetermined opening of the throttle 9 the throttle 10 starts to open and further opening of the throttle9 leads to a greater opening of the throttle 10. Air can now flow into the plenum chamber 5 and by virtue of the lower resistance to air flow into' the. inlet tube 3 via the plenum chamber 5 a relatively greater proportion of air tends to flow via this route than via the tube 13. Further opening of throttles 9 and 10 leads to an almost complete cessation of air flow through the tube 13, nearly all of the air flowing into the plenum chamber 5 and then into the intake tube 3 and the other intake tubes.

- The quantity of fuel injected by injectors 6 and 20 is I 26. The intake tubes 22 to 25 are provided respectively with injection nozzles 27, 28, 29 and 30 for the injection of fuel into the air stream. Exhaust pipes 31, 32, 33

[and 34, are connected to respective exhaust ports in the cylinder head 21, and a gallery 35 is placed so as to be in good thermal contact with these pipes. The gallery 35is connected by tube 36 to the main air inlet tube 37 feeding the plenum chamber 26. Tube 36 joins the main air intake tube 37 between first and second throttles 38 and 39. A further fuel injection nozzle 40 is .provided at the end of the gallery 35 where the tube 36 joins it. Orifices 41, 42, 43 and 44 are provided coupling the gallery 35 to the intake tubes 22, 23, 24 and 25 respectively for the passage thereto of the heated air-fuel mixture formed as described above with reference to FIG. 1.

FIG. 3 isa diagram showing the regulation of the fuel supply for the'fuel supply system shown in FIG. 2 on a founcylinder engine. In FIG. 3 components which correspond to those shown in FIG. 2 carry the same reference numerals as in-that Figure. The fuel,'which may, for example, be petrol, is fed into the system from a suitable reservoir at 50, where a pump 51, which may be operated electrically or mechanically from the enshaft 70 there is provided a pin 74. which can slide freely along slot 75provided in the link 76. The other end of the link 76 is pivoted at the pin 77 on a second arm 78 attached to the shaft 71. The arm 78' is shorter than I the arm 72.

In operation of the arrangement shown in FIG. 4 as the accelerator pedal is progressively depressed so cable 73 pulls the arm 72-to 'the'right causing it to rotate with the shaft 70 in a clockwise direction, thus opening the throttle 38. When the stud 74 reaches the righthand end of the slot 75 the link 76 is moved to the right, thus opening the throttle 39, by means of the arm 78. The relative lengths of the arms 72 and 78 are-so rethenso is the throttle 39.

gine, pressurizes the fuel in the remainder of the by respective flexible pipes 56, 57, 58 and 59, to the injection nozzles 27 28, 29 and 30. The purpose of the distribution device 55 is to equalize the fuel flow through the four injection nozzles 27 to 30. The pressurized fuel from the pump 51 also flows along pipe 60 to a second regulating valve 61, which is coupled mechanically to both throttles 38 and 39. The metered fuel supply from the valve 61 is fed along flexible pipe 62 to the injection nozzle 40 in the end of the gallery 35.

Whilst the mechanical coupling of the valve 53 to the throttle 39'follows known practice, the coupling of the regulation valve 61 to both throttles 38 and 39 is more complex. The coupling of the throttle 38 to the device 61 is similar to that of the valve 53 to the throttle 39 in that the fuel supply to the injection nozzle 40 is increased with progressive opening of the throttle 38, the rate of increase being regulated for example by a suitable cam. As the throttle 39 opens however the fuel supply fed to the injection nozzle 40 must be reduced because the air flow past the nozzle 40 is reduced when suitably shaped cam can be used to effect this control.

Referring now to FIG. 4, where again the references I means of cable 73 to the accelerator pedal of a vehicle,

for example. At the end of the arm 72 remote from the It will be appreciated from the foregoing description that many components not contributing directly to the description of the invention have been omitted, for example, no fastening meansbetween the" various parts are shown, no springs are shownfor closing the throttles and the ancilliary components of the engine shown I in FIG. 3 which might otherwise be visible have been omitted for reasons of clarity. Moreover, the invention is applicable to engines having any number of inlet ports. I v t Although referenceto a system in which a subsidiary fuel supply for low throttle openings uses a' heated gallery, his not necessary for this, gallery to be heated and the increased air velocity along the relatively smaller'airways of the subsidiary fuel supply system will in itself lead to improved mixing of the air and fuel so that the heating of the gallery may not be necessary in certainapplications. Although the heating of the gallery is carried out by means of exhaust gas in the example 1 described v above it will be appreciated that other means of heating may be used, for example, electrical heating or a water jacket through which the engine coolant circulates. In a modification of theinvention the subsidiary fuel supply may be provided by means of a carburettor in arrangement as described I stead of a fuel injection above. I

What is claimed is:

l. A fuel supply system for an intemal combustion engine having a plurality of cylinders, air supply conduitmeans and a plurality of main intake tubes connecting the cylinders to the air supply conduit means, 7

small cross-sectional area connected to the air supply conduit means, a sole secondary injection nozzle positioned to introduce fuel directly into the heated portion a I of the secondary intake tube, and secondary air control means operable to regulate air flow from the supply conduit means to the secondary intake tube, the secondary intake tube also being connected to the cylinders to supply heated fuel air mixture thereto, fuel flow con- I trol means for controlling the supply of fuel to. said main injection nozzles and to said secondary injection nozzle separately, a control mechanism for operating both said air control means and said fuel control the invention has been described with means, said control mechanism being connected to operate said fuel flow control means to admit fuel to said secondary injection nozzle only, and to operate said secondary air control means to admit air to the secondary intake tube at a rate which increases with increasing fuel supply to said secondary injection nozzle, at least up to a predetermined point, as said control mechanism is moved through a first operating range, and to then operate said fuel flow control means to initiate fuel supply to said main injection nozzles and operate the main air control means to admit air to the main intake tubes at a rate which increases with increasing fuel supply to said main injection nozzles, as said control mechanism is moved beyond said first operating range.

2. A systemas claimed in claim 1 in which said control mechanism is connected to reduce the supply of fuel to said secondary injection nozzle and the admission of air to said secondary intake tube as the supply of fuel to said main injection nozzles is increased.

3. A system according to claim 1 in which the seconsupply conduit means includes an air inlet tube in' which the air control means are located, the main air control means being positioned to receive airpassed by the secondary air control means.

5. A system according to claim 1 in which the fuel flow control means is responsive to the setting of the air control means to regulate fuel flow to the main injection nozzles in dependence on the setting of the main air control means and to regulate fuel flow to the secondary injection nozzle in dependence on the setting of both the main and the secondary air control means. a 

1. A fuel supply system for an internal combustion engine having a plurality of cylinders, air supply conduit means and a plurality of main intake tubes connecting the cylinders to the air supply conduit means, said system comprising a respective main injection nozzle positioned to introduce fuel into each intake tube and main air control means operable to regulate air flow from the supply conduit means to the main intake tubes, a secondary, heated, intake tube of relatively small crosssectional area connected to the air supply conduit means, a sole secondary injection nozzle positioned to introduce fuel directly into the heated portion of the secondary intake tube, and secondary air control means operable to regulate air flow from the supply conduit means to the secondary intake tube, the secondary intake tube also being connected to the cylinders to supply heated fuel air mixture thereto, fuel flow control means for controlling the supply of fuel to said main injection nozzles and to said secondary injection nozzle separately, a control mechanism for operating both said air control means and said fuel control means, said control mechanism being connected to operate said fuel flow control means to admit fuel to said secondary injection nozzle only, and to operate said secondary air control means to admit air to the secondary intake tube at a rate which increases with increasing fuel supply to said secondary injection nozzle, at least up to a predetermined point, as said control mechanism is moved through a first operating range, and to then operate said fuel flow control means to initiate fuel supply to said main injection nozzles and operate the main air control means to admit air to the main intake tubes at a rate which increases with increasing fuel supply to said main injection nozzles, as said control mechanism is moved beyond said first operating range.
 2. A system as claimed in claim 1 in which said control mechanism is connected to reduce the supply of fuel to said secondary injection nozzle and the admission of air to said secondary intake tube as the supply of fuel to said main injection nozzles is increased.
 3. A system according to claim 1 in which the secondary intake tube is heated by exhaust gas from the engine.
 4. A system according to claim 1 in which the air supply conduit means includes an air inlet tube in which the air control means are located, the main air control means being positioned to receive air passed by the secondary air control means.
 5. A system according to claim 1 in which the fuel flow control means is responsive to the setting of the air control means to regulate fuel flow to the main injection nozzles in dependence on the setting of the main air control means and to regulate fuel flow to the secondary injection nozzle in dependence on the setting of both the main and the secondary air control means. 